Does rdiff-backup provide capabilities on the order of 'rsync --progress'
and/or 'rsync --partial'?

I have yet to find anything. Also, 'rdiff-backup -v6' shows some things
that are close (the list of files getting mirrored with the latest sync)
but doesn't show the progress of each file, the percent of files completed
in the sync, and it shows a lot of other stuff for which I have little
interested.